FreeFloat A3 suspension system with dynamic flex panels and auto rotating shoulder straps that move with the natural movements of your body AirCushion mesh backpanel provides true breathability, eliminates pressure points and moisture-wicking cooling benefits 3D Shoulder Harness & Hipbelt Construction eliminates wrinkling and hot spots to provide hotspot free, body-hugging comfort Auto-rotating, dual-density shoulder harness with sternum strap featuring integrated safety whistle and hydration clip Available in 3 sizes to provide the Ideal fit based on borh torso length and body shape.